Remotely sensed reservoir water storage dynamics (1984–2015) and the influence of climate variability and management at global scale

Abstract

Abstract. Many thousands of large dam reservoirs have been constructed worldwide during the last seventy years to increase reliable water supplies and support economic growth. Because reservoir storage measurements are generally not publicly available, so far there has been no global assessment of long-term dynamic changes in reservoir water volume. We overcame this by using optical (Landsat) and altimetry remote sensing to reconstruct monthly water storage for 6,743 reservoirs worldwide between 1984 and 2015. We relate reservoir storage to resilience and vulnerability and analyse their response to precipitation, streamflow and evaporation. We find reservoir storage has diminished substantially for 23 % of reservoirs over the three decades but increased for 21 %. The greatest declines were for dry basins in southeastern Australia (−29 %), the USA (−10 %), and eastern Brazil (−9 %). The greatest gains occurred in the Nile Basin (+67 %), Mediterranean basins (+31 %) and southern Africa (+22 %). Many of the observed reservoir changes were explained well by changes in precipitation and river inflows, emphasising the importance of multi-decadal precipitation changes for reservoir water storage, rather than changes in net evaporation or (demand-driven) dam water releases.

Disentangling natural streamflow from reservoir regulation practices in the Alps using generalized additive models

“…Various attempts have been made to infer reservoir operation signals from different types of data sources including optical and altimetry remote sensing (Peng et al, 2006;Eldardiry and Hossain, 2019;Hou et al, 2021;Du et al, 2022), reservoir purpose, simulated inflows and water withdrawals (Hanasaki et al, 2006;Voisin et al, 2013) or in-and outflows (Turner et al, 2021). To identify the time scales most affected by reservoir operation, White et al (2005) and Shiau and Huang (2014) used the wavelet transform on both observed in-and outflow time series and compared their wavelet power spectra.…”

Historical Analysis of Reservoir Storage Trends and Resilience Across Contiguous US from 1980–2019

“…In fact, in all regions, reservoirs increase the duration of extreme events by increasing the spatial connectedness (Brunner, 2021). Decreasing storage trends have also been linked to decreasing reservoir resilience in the southwestern regions and the Mississippi basin where reservoir storage has struggled to recover after recent droughts (Hou, van Dijk, Beck, Renzullo, & Wada, 2021). This is contrasted by Giuliani and Herman (2018), who found that large dams in California with limited storage fluctuations are more drought resilient than smaller dams.…”

“…Numerous studies have noted declining reservoir storage across the US over time. Nationally, reservoir storage has declined by at least 10% over the past thirty years (Adusumilli et al, 2019;Hou et al, 2021;Randle et al, 2021;Zhao & Gao, 2019).…”

“…However, there are regional differences and not all locations have experienced declining storage (Hou et al, 2021). In general, arid regions such as the southwestern United States and more humid regions in the south-eastern United States have seen the largest storage declines when compared to the rest of the United States (Hou et al, 2021). These arid regions, such as the Southwestern United States, have historically seen the largest storage declines (Zhao & Gao, 2019).…”

“…Remote sensing is another common approach is to use to examine storage changes over large spatial scales (Adusumilli et al, 2019;Hou et al, 2021;Zhao & Gao, 2019). These methods involve gathering data from satellite missions such as GRACE or Landsat and aggregating the pixel values (usually at 0.5 degree resolution) into gridded data that can be employed in national and regional models to model reservoir dynamics (Zhao & Gao, 2019).…”